Combine flour, butter and 1 cup nuts. Press into a 13x9 inch greased pan.
Bake 20 minutes. Cool.
For the Cheesecake Layer
Beat cream cheese and powdered sugar together. Stir in one tub of the whipped topping. Spoon over crust.
For the Pistachio Layer
Beat pudding and milk for 1-2 minutes or until thickened.
Pour over cheesecake layer.
Chill for at least 2 hours.
Spread the remaining tub of whipped topping over the top of the pistachio layer.
Sprinkle with remaining walnuts.
Chill for 1-2 hours.
Cut into squares and serve cold.
Notes
Even Crust Thickness: Press the crust evenly into the pan for a sturdy base. Using the bottom of a flat measuring cup helps compact it uniformly.
Thickening the Pistachio Layer: Beat the pudding mix and milk for the full 1-2 minutes to ensure a thick, creamy filling that sets properly.
Proper Chilling Time: Chill the bars for at least 2 hours after assembling and another 1-2 hours after adding the whipped topping to help the layers set and make slicing easier.
Cool the Crust Completely: Let the crust cool fully before adding the cheesecake layer to avoid melting or sogginess.
Cut Cleanly: For neat squares, use a sharp knife and wipe it clean between slices.